1. Field of the Invention
The present invention relates to an archery bow that uses a pair of cantilever members to store and release energy for projecting an arrow and has a rotatably mounted hand grip. More specifically, the invention is an adjustable compound bow that allows the archer to vary the power characteristics of the cantilever members and other physical features of the bow in order to maximize the power and accuracy of the bow for any size and skill archer.
2. Description of Prior Art
In the field of archery equipment, the compound bow is preferable over most other bows because of its ability to reduce to some degree the amount of force needed to hold the bow at full draw. This typically gives an archer time to adjust his or her aim, or for the game to move into the archer's line of fire. The degree of force reduction is generally indicated by the percentage let-off such as, for example, a 50% let-off for a draw weight of 60 pounds suggests the archer need only apply force equal to 30 pounds to hold the bow at full draw.
However, it is difficult to design a compound bow which can meet the needs and preferences of every person due to the vast differences in size and strength of individual archers. Different individuals prefer different draw lengths and different bowstring tensions depending on their physical size and the circumstances under which they are shooting. Also a problem may arise if several individuals want to use the same bow and some of them are right-handed and others are left-handed. By creating a bow that can adjust to a wide variety of individuals it is possible to create a single bow with the capability of producing the maximum power and accuracy for each individual who uses the bow.
Consequently, there is a need for a bow which allows the archer to adjust the location of the bow hand grip in relation to the riser and the bowstring in order to adjust the draw-length of the bow. The archer will thereby have the ability to optimize his own level of comfort, power, and accuracy. The bow should permit the archer to quickly and easily adjust the tension in the bowstring and the draw characteristics of the bow. The archer will thereby have the ability to adjust the bow depending on the circumstances of the shot and depending on the strength of the archer. The bow should also provide a means for adapting to be used by either a right-handed or a left-handed archer.
Most conventional compound bows have hand grips that are fixed to the riser thereby creating a high likelihood that a archer will unwittingly draw back the bowstring in an uneven manner. This uneven draw will create torque about the hand grip which will adversely affect the arrow as it is released, thereby creating the potential for inaccurate shots.
Many types of hand grips have been created that are universally mounted on the riser to alleviate the torque about the hand grip. These universally mounted hand grips generally either allow rotation about the axis of the riser or they allow true universal rotation about all three axes. However, rotation about the axis of the arrow is generally not desired because this would create a situation where the riser would tend to want to rotate under its own weight about the axis of the arrow since the hand grip offers no resistance to this rotation. Accordingly, there is a need for a compound bow which also prevents the adverse affects of torque forces about both the axis of the riser and the axis perpendicular to both the axis of the riser and the axis of the arrow.
U.S. Design Pat. No. 282,481, issued on Feb. 4, 1986, to Donald E. Smith discloses a compound bow with a handle oriented forward of the riser. U.S. Pat. No. 4,457,287, issued on Jul. 3, 1984, to Charles E. Babington discloses an archery assembly that includes a handgrip which is universally and adjustably mounted on a bow. Neither of these patents disclose a compound bow with a hand grip that prevents rotation of the riser about the axis of the arrow while allowing rotation about the other two axes.
U.S. Design Pat. No. 361,365, issued on Aug. 15, 1995, to Gerard A. LaHaise, Sr. discloses a compound bow with a handle oriented forward of the riser. The design patent to LaHaise does not disclose a compound bow with a hand grip that prevents the adverse affects of torque forces about both the axis of the riser and the axis perpendicular to both the axis of the riser and the axis of the arrow. Nor does it disclose a bow that permits the archer to quickly and easily adjust the tension in the bowstring and the characteristics of the energy storing member.
U.S. Pat. Nos. 3,397,685, issued on Aug. 20, 1968, to Beeby G. Walker and 4,252,100, issued on Feb. 24, 1981, to Lawrence C. Rickard both disclose a universally mounted hand grip for use with archery bows. Both patents fail to disclose a hand grip that prevents rotation of the riser about the axis of the arrow while allowing rotation about the other two axes nor do they disclose the use of a grip adjustably mounted on a compound bow.
U.S. Pat. No. 3,744,473, issued on Jul. 10, 1973, to Jim Z. Nishioka discloses a compound bow with a pair of rigid rotatable members connected to the bowstring which are rotated when the bowstring is pulled and which thereby force a pair of cantilever members to bend and store energy which can be used to project the arrow. The patent to Nishioka discloses a compound bow with cantilever members that can be adjusted to vary the characteristics of those members, but the process for adjusting the members is awkward and difficult. In order for the archer to adjust the cantilever members he must attempt to hold the cantilever member in position, then he must line up the loop at the end of the linkage with holes on the bow limb, and finally he must place a pin through the hole on the limb. The entire process must then be repeated for the second cantilever member. Because there are only a finite number of holes through which the pin may be inserted, the '473 bow does not possess an infinitely variable let-off. The patent to Nishioka also fails to disclose a hand grip that prevents rotation of the riser about the axis of the arrow nor does it disclose the use of the hand grip adjustably mounted on a compound bow.
U.S. Pat. No. 4,287,867, issued on Sep. 8, 1981, to John J. Islas discloses an archery bow having a riser with upper and lower spring members from which bow limbs are pivotally suspended. The patent to Islas '867 does not disclose a compound bow with a hand grip that prevents the adverse effects of torque forces about both the axis of the riser and the axis perpendicular to both the axis of the riser and the axis of the arrow.
Both U.S. Pat. Nos. 4,667,649, issued on May 26, 1987, to Stanley A. Humphrey and 4,781,168, issued on Nov. 1, 1988, to Wayne L. Lester disclose compound bows which use several resilient cantilever members and a pulley system to store and release power for shooting an arrow. U.S. Pat. No. 5,388,564, issued on Feb. 14, 1995, to John J. Islas discloses a compound bow with a pair of rotatable rigid members which when rotated store energy in a pair of cantilever members and which are synchronized using a timing cable hidden within the frame of the riser. None of these patents disclose hand grips that prevent rotation of the riser about the axis of the arrow while allowing rotation about the other two axes nor do they disclose the use of a grip adjustably mounted on a compound bow. Similarly, neither do French Patent Number 2,304,887, published on Oct. 15, 1976 nor British Patent Number 1,578,326, published on Nov. 5, 1980.
While forward-handles have been used with compound bows before, as seen in The Forward-Handle and Overdraw Bows, Freddie Troncoso, Bow & Arrow, June 1982, and FAST CAT--The Martin Jaquar Forward Handle Cam Bow Proves To Be A Fast Hunter, C. R. Learn, Bow & Arrow, October 1983, these articles fail to disclose the benefits of using a rotatably mounted hand grip that prevents rotation about the axis of the arrow.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a twin limb bow solving the aforementioned problems is desired.